Le confinement de polymères incompatibles au sein de particules induit une séparation de phase et conduit à la formation de morphologies particulières (cœur-écorce, hémisphérique…). Cette nanostructuration est à l’origine de propriétés de filmification particulières qui justifient l’utilisation des particules polymères composites dans le cadre d’applications comme la formulation de peintures ou de revêtements. Ce travail s’intéresse au développement d’approches permettant de préparer ces particules polymères composites en une seule étape et en milieu aqueux. La stratégie proposée repose sur le couplage « en simultané » de deux polymérisations distinctes: la polymérisation de cyclooléfines par métathèse (ROMP) et la polymérisation radicalaire par transfert d’atome (ATRP). Après avoir mis en évidence les difficultés liées au couplage de la ROMP et de l’ATRP en milieu dispersé aqueux, deux approches originales faisant intervenir respectivement des conditions de miniémulsion et de microémulsion sont proposées. Pour chacune d’elles, la présentation du principe de la synthèse et l’analyse de ses résultats précèdent l’étude morphologique des particules produites. / So as to broaden the scope of their applications in paints, coatings and impact-resistant plastics, many investigations have been dedicated to the preparation of nanostructured colloids over the past decades. Original morphologies including core-shell, hemispherical and complex occluded structures (raspberry-like, golf ball-like, octopus-like) can now be readily prepared. This work proposes a new straightforward one-pot, one-step, one-catalyst strategy to prepare polymer composite particles based on the simultaneous combination of two mechanistically distinct polymerizations in aqueous dispersed media. Norbornene (NB) and methyl methacrylate (MMA) were converted via Ring-Opening Metathesis Polymerization (ROMP) and Atom-Transfer Radical Polymerization (ATRP), respectively. Two original routes, designed to ensure simultaneous ROMP and ATRP, respectively under mini- and microemulsion conditions, are proposed. Both are successively reviewed on chemical and colloidal levels. Specific attention is paid to the morphologies of the prepared particles.

The goal of this work was to synthesize complex macromolecular architectures such as dendrimers and dendronized polymers, and evaluate the effect from the dendrons on the optical and material properties. The work presented in this doctoral thesis, Dendrimers and Dendronized Polymers - Synthesis and Characterization, is divided into one minor and one major part. The first part deals with the synthesis and characterization of two sets of dendritic porphyrins based on 2,2-bis(methylol)propionic acid (bis-MPA). The second part deals with the synthesis and characterization of dendronized poly(hydroxyl ethyl methacylate), dendronized poly(norbornene), and dendronized triblock copolymers, were the pendant dendrons are based on bis-MPA. Both free-base and zinc containing dendritic porphyrins was synthesized up to the fifth generation by employing iterative ester coupling utilizing the acetonide protected anhydride of bis-MPA as generic building block. First and second generation dendron bearing methacrylates based on 2-hydroxyethyl methacrylate were also synthesized by utilizing the acetonide protected anhydride of bis-MPA, and subsequently polymerized by atom transfer radical polymerization. By adopting a divergent “graft-to” approach starting from the first generation dendronized poly(hydroxyl ethyl methacrylate), well-defined dendronized polymers with acetonide, hydroxyl, acetate and hexadecyl surface functionality were obtained. By utilizing the same divergent iterative esterfication, first to fourth generation dendron functionalized norbornenes were synthesized. These monomers were polymerized by ring-opening metathesis polymerization, utilizing either Grubbs´ first or second generation catalyst. Acrylate functional first to fourth generation monomers were synthesized by the copper(I) catalyzed “click” coupling of azido functional dendrons and propargyl acrylate. The monomers were polymerized to dendronized triblock copolymers by reversible addition-fragmentation chain transfer polymerization, utilizing a difunctional poly(methyl methacrylate) as macro chain transfer agent. The bulk properties of the dendronized poly(hydroxyl ethyl methacrylate) and poly(norbornene) were investigated by dynamic rheological measurements and differential scanning calorimetry. It was found that all the acetonide functional bis-MPA based dendronized polymers had glass transitions temperatures in a similar range. The rheological behaviour showed that for the dendronized polymers having the same backbone length the complex viscosity as a function of functionality was independent of the surface functionality of the polymer. The generation number of the polymer had a profound influence on the complex viscosity, changing form a Newtonian behaviour to a shear thinning behaviour when the generation of the dendrons was increased from two to four. The dendronized poly(norbornene) had increasingly shorter backbone lengths for each generational increase, and for the materials set with comparably lower degree of polymerization, the G’ part of the complex modulus was mostly affected by attaching larger dendrons. In the case of the sample set of higher degree of polymerization, the second, third, and fourth generation samples had similar slopes of the G’ and G” curves, indicating a similar relaxation behaviour. / QC 20100914

Les acides biliaires sont des composés naturels existants dans le corps humain. Leur biocompatibilité, leur caractère amphiphile et la rigidité de leur noyau stéroïdien, ainsi que l’excellent contrôle de leurs modifications chimiques, en font de remarquables candidats pour la préparation de matériaux biodégradables pour le relargage de médicaments et l'ingénierie tissulaire. Nous avons préparé une variété de polymères à base d’acides biliaires ayant de hautes masses molaires. Des monomères macrocycliques ont été synthétisés à partir de diènes composés de chaînes alkyles flexibles attachées à un noyau d'acide biliaire via des liens esters ou amides. Ces synthèses ont été réalisées par la fermeture de cycle par métathèse, utilisant le catalyseur de Grubbs de première génération. Les macrocycles obtenus ont ensuite été polymérisés par ouverture de cycle, entropiquement induite le catalyseur de Grubbs de seconde génération. Des copolymères ont également été préparés à partir de monolactones d'acide ricinoléique et de monomères cycliques de triester d’acide cholique via la même méthode. Les propriétés thermiques et mécaniques et la dégradabilité de ces polymères ont été étudiées. Elles peuvent être modulées en modifiant les différents groupes fonctionnels décorant l’acide biliaire et en ayant recours à la copolymérisation. La variation des caractéristiques physiques de ces polymères biocompatibles permet de moduler d’autres propriétés utiles, tel que l’effet de mémoire de forme qui est important pour des applications biomédicales. / Bile acids are natural compounds in the body. Their biocompatibility, facial amphiphilicity, rigidity of steroid nucleus, and ease of chemical modification make them excellent candidates as building blocks for making biodegradable materials used in drug delivery and tissue engineering applications. We have prepared main-chain bile acid-based polymers having high molecular weights. Macrocyclic monomers were synthesized from dienes, which consist of flexible alkyl chains attached to a bile acid core through either ester or amide linkages, via ring closing metathesis using first-generation Grubbs catalyst. They were polymerized using entropy-driven ring-opening metathesis polymerization using second-generation Grubbs catalyst. Copolymers were also prepared from monolactone of ricinoleic acid and cholic acid-based cyclic triester monomer via the same method. The thermal and mechanical properties and degradation behaviours of these polymers have been investigated. The properties can be tuned by varying the chemical linking with the bile acid moiety and by varying the chemical composition of the polymers such as copolymerization with ricinoleic acid lactones. The tunability of the physical properties of these biocompatible polymers gives access to a range of interesting attributes. For example, shape memory properties have been observed in some samples. This may prove useful in the design of materials for biomedical applications.

This critical review summarizes recent developments in the fabrication of patterned polymer brushes. As top-down lithography reaches the length scale of a single macromolecule, the combination with the bottom-up synthesis of polymer brushes by surface-initiated polymerization becomes one main avenue to design new materials for nanotechnology. Recent developments in surface-initiated polymerizations are highlighted along with diverse strategies to create patterned polymer brushes on all length scales based on irradiation (photo- and interference lithography, electron-beam lithography), mechanical contact (scanning probe lithography, soft lithography, nanoimprinting lithography) and on surface forces (capillary force lithography, colloidal lithography, Langmuir–Blodgett lithography) (116 references). / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.

This critical review summarizes recent developments in the fabrication of patterned polymer brushes. As top-down lithography reaches the length scale of a single macromolecule, the combination with the bottom-up synthesis of polymer brushes by surface-initiated polymerization becomes one main avenue to design new materials for nanotechnology. Recent developments in surface-initiated polymerizations are highlighted along with diverse strategies to create patterned polymer brushes on all length scales based on irradiation (photo- and interference lithography, electron-beam lithography), mechanical contact (scanning probe lithography, soft lithography, nanoimprinting lithography) and on surface forces (capillary force lithography, colloidal lithography, Langmuir–Blodgett lithography) (116 references). / Dieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.